Apparatus for continuously dissolving pulverulent material in a liquid

ABSTRACT

METHOD AND APPARATUS FOR CONTINUOUSLY DISSOLVING A PULVERULENT MATERIAL IN A LIQUID. THE PULVERULENT MATERIAL IS SPRAYED WITH THE FINELY DIVIDED LIQUID AND THE SOLUTION IS CAUSED TO FLOW IN A THIN LAYER ALONG THE INNER SURFACE OF A CHAMBER.

June 11,1974 w. Laum ETAL 3,816,427

APPARATUS FOR CONTINUOUSLY DISSOLVING PULVERULENT MATERIAL IN A LIQUID Filed March 14, 1973 3,816,427 APPARATUS FOR CONTINUOUSLY DISSOLVING PULVERULEN T MATERIAL IN A LIQUID Willi Liiliger, Grunegg, and Rudolf Schmied, Tonisbach, both of Konolfingen, Switzerland Claims priority, application Switzerland, Mar. 22, 1972, 4,243/72 Filed Mar. 14, 1973, Ser. No. 341,293 Int. Cl. B01d 11/02 US. Cl. 23-271 7 Claims ABSTRACT OF THE DISCLOSURE Method and apparatus for continuously dissolving a pulverulent material in a liquid. The pulverulent material is sprayed with the finely divided liquid and the solution is caused to flow in a thin layer along the inner surface of a chamber.

The invention relates to an improved method and apparatus for continuously dissolving a pulverulent material in a liquid.

According to the invention, the method consists in spraying the pulverulent material with the finely divided liquid and. causing the solution to flow in a thin layer along the inner surface of a chamber.

The apparatus according to the invention comprises a chamber having an upper opening and outletting in its lower part into a pipe, a supply channel running along the edge of said upper opening, said upper opening being provided with a pulverulent material feeding duct and a liquid spraying nozzle substantially coaxial with said duct. In a preferred embodiment, the apparatus comprises also a mixing nozzle outletting into the lower part of the chamber.

In the drawing:

The figure is a partial vertical section and diagrammatic view of an apparatus according to the invention.

The apparatus comprises mainly a chamber 1 having an upper opening 2 and outletting in its lower part into a pipe 3. An open supply channel 4 runs along the edge of the upper opening 2. In a preferred embodiment, this edge is notched and the channel 4 is fed tangentially by the pipe 5. Baffles 6 insure a regular distribution of the flow on the periphery of the chamber opening. In the center of the opening 2 are placed in a pulverulent material feeding duct 7 and a liquid spraying nozzle 8 coaxial with the duct 7. As shown, the nozzle 8 extends below the plane of the feeding duct 7.

The outlet pipe 3 is connected to a pump 9 which feeds the discharge pipe 10. In a preferred embodiment, a mixing nozzle 11 outlets into the lower part of the chamber 1, below the level of the solution collected at the bottom of the chamber.

In the embodiment illustrated by the drawing, two pipes, each provided with a tap, branch out of the pipe 10, one connected to the mixing nozzle 11, the other to the supply channel 4. In other embodiments, the nozzle 11 and/or the channel 4 are supplied directly with the dissolving liquid, in parallel with the nozzle 8.

In the embodiment illustrated, a tank 12 and a pump 13 are connected to the outlet pipe 3. In a preferred embodiment, the discharge pipe 10 is connected to a holding tank.

In operation, the pulverulent material to be dissolved flows out of the central duct 7 into the upper opening 2. The liquid supplied at a pressure of 3 to 10 kg./cm. squirts out of the nozzle 8 towards the inner surface of the chamber 1. The spray has a conical shape, with an angle at the top of 60 to 120, and intersects the flow of pulverulent material so as to carry the material onto the inner surface of the chamber 1. The liquid runs down in a thin layer United States Patent along the inner surface of the chamber 1, entraining and dissolving the material. The solution is collected at the lower part of the chamber, its level not exceeding about /3 of the total height of the chamber, and comes out by the outlet pipe 3. The solution is pumped out of the chamber into the discharge pipe 10. Part of this flow is diverted to the mixing nozzle 11 and returns under the level of the solution collected at the lower part of the chamber 1, making the solution turbulent. Another part of the solution is directed to the supply channel 4 where it overflows the notched edge of the upper opening and runs in a thin layer along the inner surface of the chamber 1.

The proportion of the solution returning to the chamber 1 through the nozzle 11 and/or the channel 4 depends from the material, the concentration, the flow rate and the efficiency desired. For example, if the input and output are relatively small, it may be necessary to recirculate a large proportion of the solution in order to have a homo geneous liquid film along the inner surface of the chamber 1. On the contrary, if the concentration of material is low and/or the flow rate important, it is not necessary to divert a part of the solution from the pipe 10. In general, the proportion of the flow which is diverted and recirculated represents 50 to 500% of the inand output of the apparatus. The solids concentration can be as high as The temperature of the components depends on their nature. In most cases, the liquid will be heated and the pulverulent material be at ambient temperature.

The solution running in a thin layer, it degasses the powder and reduces the tendency to foam.

With the tank 12 and the pump 13, liquids such as liquid fat can be introduced into the solution.

The apparatus described is particularly suitable for recombining milk from milk powder. Its use is, however, not limited to food products and it can be used also to dissolve chemical products or to mix fine pulverulent material with liquids for example.

EXAMPLE 1 To obtain an output of 5000 kg. per hour of evaporated milk with 25.9% dry matter content, 927.5 kg./h. of skimmed milk powder having 97% dry matter content at 20 C. in introduced b the central duct 7. The total input of water at 70 C. is 3677.5 kg./h., of which 1250 kg./h. are sprayed by the nozzle 8 and 2427.5 kg./h. flow from the channel 4. 395 kg./h. of milk fat at 40 C. are introduced into the pipe 3 by the pump 13. Of the flow coming out of the chamber 1, 2500 kg./h. are recirculated by the channel 4 and 2500 kg./h. by the mixing nozzle 11.

EXAMPLE 2 To obtain an output of 5000 kg./h. of sweetened condensed milk with 72.68% dry matter content, 1135.0 kg./ h. skimmed milk powder and 2178.5 kg./h. sugar are introduced together by the central duct 7. 1332.0 kg./h. water are sprayed by the nozzle 8 and 354.5 kg./h. milk fat are injected into the pipe 3 by the pump 13. 2000 kg./h. return into the chamber 1 by the channel 4 and the same hourly quantity by the mixing nozzle 11.

We claim:

1. Apparatus for continuously dissolving a pulverulent material in a liquid comprising a cylindrical chamber for a liquid level less than /3 the height of said chamber, said chamber having an upper opening including an upper edge notched about its circumference and outletting in its lower part into an outlet pipe, a supply channel running circumferentially around the edge of said upper opening, said upper opening being provided with a coaxial pulverulent material feeding duct, a liquid spraying nozzle substantially coaxial with said duct and extending below the plane of the lower end of said duct for supplying a spray having a conical shape with an angle at the top of 60 to 120, a mixing nozzle outletting into the lower part of the chamber, baffies in said suppl channel to insure a regular distribution of the fiow on the periphery of the chamber opening and conduit means connecting said supply chamber and said mixing nozzle with a source of liquid.

2. Apparatus according to claim 1 in which the supply channel is fed tangentially.

3. Apparatus according to claim 1 in which a discharge pipe of the chamber branches out to a mixing nozzle placed below the level of the liquid in the chamber.

4. Apparatus according to claim 1 in which a discharge pipe of the chamber branches out to the supply channel.

5. An apparatus for continuously dissolving a pulverulent material in a liquid comprising a cylindrical chamber for containing a level of solution, said chamber having an upper opening notched about its circumference;

a supply channel extending around the circumference of said upper opening to supply liquid to said notches to thereby provide a thin layer of descending liquid onto the inner surface of said chamber;

an outlet pipe connected to a lower part of said chamber for the discharge of solution;

a feeding duct coaxial within said upper opening of said chamber for feeding pulverulent material into said chamber;

a liquid spraying nozzle coaxial of said duct and extending below the plane of the lower end of said duct for spraying a spray of liquid into a flow of pulverulent material and into the thin layer of liquid on said inner surface of said chamber;

a mixing nozzle within the lower part of said chamber, and conduit means connecting said supply channel and said mixing nozzle with a source of liquid.

6. An apparatus as set forth in claim 5 wherein said nozzle forms a spray having a conical shape with an angle at the top of to 7. An apparatus as set forth in claim 5 which further comprises a discharge pipe connected to said outlet pipe to receive solution therefrom, a pipe connecting said discharge pipe to said supply channel to recirculate solution thereto and a mixing nozzle within said chamber connected to said discharge pipe to recirculate solution.

References Cited UNITED STATES PATENTS 3,606,093 9/ 1971 Morse 23271 3,343,919 9/1967 Miller 23-271 3,366,458 1/1968 Jori 23312 A 2,997,373 8/1961 Stephens 23272.6 R 3,595,296 7/1971 Berg 15913 A 2,055,836 9/1936 Cowles 23-271 3,273,629 9/1966 Sargeant 159--13 A 2,593,503 4/1952 Tomlinson 15913 A FOREIGN PATENTS 642,417 10/1927 France 23-27l 1,209,119 10/1970 Great Britain 159-13 A 923,889 5/1959 Great Britain 159-13 A NORMAN YUDKOFF, Primary Examiner S. J. EMERY, Assistant Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFIEATE OF CORRECTION Inventor(s) Willi Loligor ct It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

This application is assigned to --Societe D'Assistance Technique Pour Produits Nestle of Lausanne, Switzerland.---

Column 2, line 15, "from" should be ---on--.

Signed and sealed this 12th day of November 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents FORM USCOMM-DC 60376-P69 1L5. GQVERNHENT FRINTHIG OFFICE C 1,. 0-38-33. 

